U.S. patent application number 15/076896 was filed with the patent office on 2016-11-10 for imaging apparatus and intraoral camera.
The applicant listed for this patent is RF CO., LTD.. Invention is credited to Chihiro KOMAMURA, Akio KOYANAGI, Jiro MARUYAMA, Akio SUNOHARA, Yusuke YABANA.
Application Number | 20160330365 15/076896 |
Document ID | / |
Family ID | 55127909 |
Filed Date | 2016-11-10 |
United States Patent
Application |
20160330365 |
Kind Code |
A1 |
MARUYAMA; Jiro ; et
al. |
November 10, 2016 |
IMAGING APPARATUS AND INTRAORAL CAMERA
Abstract
An imaging apparatus includes a lens, a moving mechanism, an
imaging device, and a controller. The moving mechanism moves the
lens in the optical axis direction. The controller drives, in
response to an input of an imaging instruction, the moving
mechanism to move the lens to a plurality of imaging positions from
one of infinity and close-up ends to the other and drives the
imaging device when the lens is positioned at each of the imaging
positions. Since the interior of an oral cavity, for example, is
difficult to capture, the focus can hardly be adjusted on it with
high accuracy when an autofocus mechanism is used. However, since
the lens is moved to the plurality of imaging positions in the
optical axis direction in response to each input of the imaging
instruction to obtain captured images, an in-focus image can be
reliably obtained.
Inventors: |
MARUYAMA; Jiro; (Nagano,
JP) ; YABANA; Yusuke; (Nagano, JP) ; KOYANAGI;
Akio; (Nagano, JP) ; KOMAMURA; Chihiro;
(Nagano, JP) ; SUNOHARA; Akio; (Nagano,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RF CO., LTD. |
Nagano |
|
JP |
|
|
Family ID: |
55127909 |
Appl. No.: |
15/076896 |
Filed: |
March 22, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03B 15/14 20130101;
H04N 5/2253 20130101; H04N 5/2254 20130101; A61B 1/0002 20130101;
A61B 1/24 20130101; A61B 1/00006 20130101; H04N 5/2252 20130101;
A61B 1/00188 20130101; A61B 1/045 20130101; H04N 5/2256 20130101;
G03B 3/10 20130101; H04N 5/23212 20130101; H04N 2005/2255
20130101 |
International
Class: |
H04N 5/232 20060101
H04N005/232; A61B 1/045 20060101 A61B001/045; A61B 1/00 20060101
A61B001/00; H04N 5/225 20060101 H04N005/225; A61B 1/24 20060101
A61B001/24 |
Foreign Application Data
Date |
Code |
Application Number |
May 7, 2015 |
JP |
2015-094735 |
Claims
1. An imaging apparatus comprising: a lens that focuses light from
an object; a moving mechanism that moves the lens in an optical
axis direction; an imaging device that captures an image of the
object formed by the lens to obtain a captured image; and a
controller for driving, in response to an input of an imaging
instruction, the moving mechanism to move the lens to a plurality
of imaging positions from one of infinity and close-up ends to the
other and driving the imaging device when the lens is positioned at
each of the plurality of imaging positions.
2. The imaging apparatus according to claim 1, wherein the moving
mechanism includes: a magnet that is located outside the lens in a
radial direction and moves together with the lens; a vibrating
plate that supports the magnet and the lens, and generates a
restoring force in a direction to return the magnet and the lens to
a home position in accordance with an amount of shift of the magnet
and the lens from the home position in the optical axis direction;
and a coil that is located outside the magnet in the radial
direction and generates a magnetic force to move the magnet and the
lens in the optical axis direction upon power supply, and the
controller changes an amount of power supplied to the coil, to move
the magnet and the lens to the plurality of imaging positions.
3. The imaging apparatus according to claim 1, wherein the
controller moves the lens to the plurality of imaging positions,
the number of which is equal to a frame rate of the imaging device,
from one of the infinity and close-up ends to the other in response
to the input of the imaging instruction.
4. The imaging apparatus according to claim 2, wherein the
controller moves the lens to the plurality of imaging positions,
the number of which is equal to a frame rate of the imaging device,
from one of the infinity and close-up ends to the other in response
to the input of the imaging instruction.
5. The imaging apparatus according to claim 1, further comprising a
memory that stores the image captured when the lens is positioned
at each of the imaging positions, and the controller assigns as
metadata a number corresponding to the imaging position of the lens
to the image captured at each of the imaging positions.
6. The imaging apparatus according to claim 2, further comprising a
memory that stores the image captured when the lens is positioned
at each of the imaging positions, and the controller assigns as
metadata a number corresponding to the imaging position of the lens
to the image captured at each of the imaging positions.
7. The imaging apparatus according to claim 3, further comprising a
memory that stores the image captured when the lens is positioned
at each of the imaging positions, and the controller assigns as
metadata a number corresponding to the imaging position of the lens
to the image captured at each of the imaging positions.
8. The imaging apparatus according to claim 4, further comprising a
memory that stores the image captured when the lens is positioned
at each of the imaging positions, and the controller assigns as
metadata a number corresponding to the imaging position of the lens
to the image captured at each of the imaging positions.
9. An intraoral camera comprising: a lens that focuses light from
an object; a moving mechanism that moves the lens in an optical
axis direction; an imaging device that captures an image of the
object formed by the lens to obtain a captured image; a memory for
storing the captured image; a controller for driving, in response
to an input of an imaging instruction, the moving mechanism to move
the lens to a plurality of imaging positions from one of infinity
and close-up ends to the other and stores, in the memory, the image
captured when the lens is positioned at each of the imaging
positions; and a case that extends in a first direction, for
accommodating the lens, the moving mechanism, the imaging device,
the memory, and the controller, wherein the lens, the moving
mechanism, and the imaging device are arranged to match the optical
axis direction with a direction perpendicular to the first
direction within a distal end of the case in the first direction.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an imaging apparatus and an
intraoral camera.
[0003] 2. Description of the Related Art
[0004] An intraoral camera that captures an image of the interior
of the oral cavity of a patient is known (see, for example, Patent
Literature 1). In the intraoral camera according to Patent
Literature 1, the distal end of a body case is inserted into the
oral cavity of the patient. Light from an object within the oral
cavity enters the body case from an imaging window provided at the
distal end of the body case. The light is guided to an imaging
device provided within the central portion of the body case via an
optical system. Within the central portion of the body case, a
focusing lens and an autofocus mechanism are provided upstream of
the imaging device. According to Patent Literature 1, the autofocus
mechanism moves the focusing lens in the optical axis direction to
carry out focusing.
PRIOR ART REFERENCES
[0005] Patent Literature 1: Japanese Patent Application Laid-Open
No. 2012-75690
[0006] Unfortunately, Patent Literature 1 poses the following
problems. That is, the use of the autofocus mechanism leads to a
large, heavy optical system for imaging. This makes the intraoral
camera hard to use.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide an
imaging apparatus and an intraoral camera that can miniaturize an
optical system for imaging and reduce the weight thereof.
[0008] A first aspect of the present invention is an imaging
apparatus including a lens that focuses light from an object, a
moving mechanism that moves the lens in an optical axis direction,
an imaging device that captures an image of the object formed by
the lens to obtain a captured image, and a controller for driving,
in response to an input of an imaging instruction, the moving
mechanism to move the lens to a plurality of imaging positions from
one of infinity and close-up ends to the other and driving the
imaging device when the lens is positioned at each of the imaging
positions.
[0009] Since the interior of an oral cavity, for example, is
difficult to capture, the focus can hardly be adjusted on it with
high accuracy when an autofocus mechanism is used. However,
according to the present invention, since the lens is moved to the
plurality of imaging positions in the optical axis direction in
response to each input of an imaging instruction to obtain captured
images, an in-focus image can be reliably obtained. The imaging
apparatus may store the obtained, captured image in the memory or
transmit it to an external device.
[0010] According to the present invention, since an autofocus
mechanism is omitted, a compact, lightweight optical system for
imaging can be obtained. Further, according to the present
invention, a compact optical system for imaging can be provided,
thus increasing the positional degree of freedom of the optical
system for imaging in the imaging apparatus.
[0011] In the present invention, the moving mechanism may include a
magnet that is located outside the lens in a radial direction and
moves together with the lens, a vibrating plate that supports the
magnet and the lens, and generates a restoring force in a direction
to return the magnet and the lens to a home position in accordance
with the amount of shift of the magnet and the lens from the home
position in the optical axis direction, and a coil that is located
outside the magnet in the radial direction and generates a magnetic
force to move the magnet and the lens in the optical axis direction
upon power supply. The controller may change the amount of power
supplied to the coil, to move the magnet and the lens to the
plurality of imaging positions.
[0012] When the coil is located on the lens side and the magnet
surrounds the coil and the lens, the coil must be wired inside the
magnet. This complicates the structure of the moving mechanism.
[0013] According to the present invention, the magnet is located on
the lens side and the coil surrounds the magnet and the lens.
Hence, the coil can be wired outside the moving mechanism and this
can simplify the structure of the moving mechanism.
[0014] In the present invention, the controller may move the lens
to the plurality of imaging positions, the number of which is equal
to the frame rate of the imaging device, from one of the infinity
and close-up ends to the other in response to the input of the
imaging instruction.
[0015] According to the present invention, imaging requires 1 sec.
or less for every imaging position in one imaging instruction.
Hence; the speed of the imaging operation of the imaging apparatus
can be kept high enough to release user's stress.
[0016] In the present invention, the imaging apparatus may include
a memory that stores the image captured when the lens is positioned
at each of the imaging positions. The controller may assign as
metadata a number corresponding to the imaging position of the lens
to the image captured at each of the imaging positions.
[0017] According to the present invention, the captured images can
be easily managed.
[0018] A second aspect of the present invention is an intraoral
camera including a lens for focusing light from an object, a moving
mechanism for moving the lens in an optical axis direction, an
imaging device for capturing an image of the object formed by the
lens to obtain a captured image, a memory for storing the captured
image, a controller for driving, in response to an input of an
imaging instruction, the moving mechanism to move the lens to a
plurality of imaging positions from one of infinity and close-up
ends to the other and stores, in the memory, the image captured
when the lens is positioned at each of the imaging positions, and a
case that extends in a first direction, for accommodating the lens,
the moving mechanism, the imaging device, the memory, and the
controller. The lens, the moving mechanism, and the imaging device
are arranged to match the optical axis direction with a direction
perpendicular to the first direction within a distal end of the
case in the first direction.
[0019] According to the present invention, an optical system for
imaging including a lens, a moving mechanism, and an imaging device
is positioned on the distal end side of the intraoral camera in the
first direction. Hence, a battery can be positioned on the proximal
end side of the intraoral camera in the first direction to achieve
wireless communication by the intraoral camera. Further, according
to the second aspect, since the optical system for imaging is
positioned to match the optical axis direction with a direction
perpendicular to the first direction, the use of the intraoral
camera can be facilitated.
BRIEF DESCRIPTION OF DRAWINGS
[0020] FIG. 1 is a diagram illustrating an intraoral imaging
system;
[0021] FIG. 2 is a plan view illustrating a surface of the
intraoral camera, on which an imaging window is provided;
[0022] FIG. 3 is a perspective view illustrating a board and an
imaging unit;
[0023] FIG. 4 is a cross-sectional view of the imaging unit;
[0024] FIG. 5 is a flowchart for explaining the operation of the
intraoral camera;
[0025] FIG. 6 includes diagrams for explaining one example of a
method of moving a focusing lens;
[0026] FIG. 7 is a cross-sectional view illustrating an example of
a capsule endoscope to which an imaging apparatus according to the
present invention is applied;
[0027] FIG. 8 is a cross-sectional view illustrating another
example of a capsule endoscope to which the imaging apparatus
according to the present invention is applied; and
[0028] FIG. 9 is a cross-sectional view illustrating an example of
a joystick endoscope to which the imaging apparatus according to
the present invention is applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] Embodiments will be described below with reference to the
accompanying drawings.
First Embodiment
[0030] FIG. 1 is a diagram illustrating an intraoral imaging system
100.
[0031] The intraoral imaging system 100 includes an intraoral
camera 1 (imaging apparatus), a relay device 200, and an external
device 300.
[0032] The intraoral camera 1 captures an image of an object such
as a row of teeth in an oral cavity. The intraoral camera 1
communicates with the relay device 200 by radio to transmit the
captured image to the external device 300 via the relay device
200.
[0033] The intraoral camera 1 includes a case 10 extending in the X
direction.
[0034] The case 10 includes a gripping portion 2 extending in the X
direction, and an insertion portion 3 which extends in the X
direction from one end of the gripping portion 2 and is narrower
than the gripping portion 2. In the following description, the X
direction is defined to be negative toward the gripping portion 2
and positive toward the insertion portion 3. The gripping portion 2
has an almost cylindrical outer shape. The insertion portion 3 has
an almost rectangular parallelepiped outer shape.
[0035] The insertion portion 3 is inserted into an oral cavity. An
imaging window 31 is provided at the distal end of the insertion
portion 3. The imaging window 31 opens in the Y direction
perpendicular to the X direction. The intraoral camera 1 captures
an image of the object via the imaging window 31. In the following
description, the Y direction is defined to be positive from the
inside of the intraoral camera 1 to the outside and negative from
the outside of the intraoral camera 1 to the inside. The insertion
portion 3 accommodates a memory 52. The memory 52 can store, for
example, 64 captured images.
[0036] The gripping portion 2 includes a power supply switch 21
which turns on and off the intraoral camera 1 by sliding. The
gripping portion 2 includes an imaging button 22 positioned more in
the +X direction and playback buttons 23A and 23B positioned more
in the -X direction. The user can capture an image of the object by
pressing the imaging button 22 with, for example, his or her
forefinger while gripping the gripping portion 2. The gripping
portion 2 accommodates a battery 24 which supplies power to each
unit of the intraoral camera 1.
[0037] The external device 300 can be implemented using a display
only or a PC (Personal Computer).
[0038] FIG. 2 is a plan view illustrating a surface of the
intraoral camera 1 in the +Y direction, on which the imaging window
31 is provided.
[0039] The imaging window 31 is a hole formed at the distal end of
the insertion portion 3 in the +X direction. The imaging window 31
is sealed with a transparent film. Light from the object enters the
intraoral camera 1 from the imaging window 31.
[0040] Four irradiation windows 32 surround the imaging window 31.
The irradiation windows 32 allow white LEDs 401 (see FIG. 3) and
405-nm LEDs 402 (see FIG. 3) mounted in the insertion portion 3 to
be exposed to the outside. The white LEDs 401 emit high-intensity
white light. The 405-nm LEDs 402 emit light in a wavelength range,
with 405 nm as its center.
[0041] Two white LEDs 401 and two 405-nm LEDs 402 are provided. The
pair of white LEDs 401 are opposed to each other across the imaging
window 31 on the surface of the insertion portion 3. The pair of
405-nm LEDs 402 are also opposed to each other across the imaging
window 31 on the surface of the insertion portion 3. The pairs of
white LEDs 401 and 405-nm LEDs 402 are respectively positioned in
correspondence with the vertices of a square.
[0042] The gripping portion 2 includes a selecting switch 25. In
the intraoral camera 1, sliding the selecting switch 25 allows LEDs
which illuminate the object to be switched to the white LEDs 401 or
the 405-nm LEDs 402.
[0043] FIG. 3 is a perspective view illustrating a board 5 and an
imaging unit 4.
[0044] The board 5 is accommodated in the insertion portion 3. A
controller 51, the memory 52, and the imaging unit 4 are mounted on
the board 5. The controller 51 controls the overall intraoral
camera 1. The imaging unit 4 captures an image of the object via
the imaging window 31. The white LEDs 401 and the 405-nm LEDs 402
are mounted on the imaging unit 4. The imaging unit 4 has its
optical axis direction coinciding with the Y direction within the
distal end of the insertion portion 3 in the X direction.
[0045] FIG. 4 is a cross-sectional view of the imaging unit 4. FIG.
4 shows a schematic view for explaining the imaging principle. The
white LEDs 401 and the 405-nm LEDs 402, for example, are not
illustrated in FIG. 4.
[0046] The imaging unit 4 includes an imaging device 403 such as a
CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide
Semiconductor), a low-pass filter 404, a cover glass 405, a holder
406, a coil 407, a focusing lens 408, a vibrating plate 409, a
magnet 410, an iris 411, and a holding member 412.
[0047] The imaging device 403 is mounted on the board 5. The
imaging device 403 captures an object image formed on the imaging
device 403 via the focusing lens 408 to obtain a captured image.
The captured image is stored in the memory 52. In this embodiment,
the frame rate of the imaging device 403 is 30 FPS (Frame Per
Second).
[0048] The low-pass filter 404 and the cover glass 405 are stacked
on the imaging device 403.
[0049] The holder 406 has a cylindrical shape. The holder 406 has
small- and large-diameter portions 406A and 406B. The
large-diameter portion 406B is formed more in the -Y direction than
the small-diameter portion 406A and covers the periphery of the
imaging device 403.
[0050] The coil 407 is wound in an annular shape and positioned
outside the small-diameter portion 406A. The coil 407 is located
outside the magnet 410 in the radial direction. The magnet 410
supports the focusing lens 408. Supplying power to the coil 407
generates a magnetic force between the coil 407 and the magnet 410
to move the magnet 410 and the focusing lens 408 in the optical
axis direction (.+-.Y directions) of the focusing lens 408.
[0051] The vibrating plate 409 has an annular shape and has its
outer peripheral portion fixed to the end face of the holder 406 in
the +Y direction. The end face of the magnet 410 in the +Y
direction is fixed to the inner peripheral portion of the vibrating
plate 409. The vibrating plate 409 supports the magnet 410 and the
focusing lens 408 at a home position in the optical axis direction
in a normal state in which no current is supplied to the coil
407.
[0052] When a current is supplied to the coil 407 to move the
magnet 410 and the focusing lens 408 in the optical axis direction,
the vibrating plate 409 applies a restoring force to the magnet 410
and the focusing lens 408 in accordance with the amount of shift of
the magnet 410 and focusing lens 408 from the home position in the
optical axis direction. The vibrating plate 409 also functions as a
guide which moves the magnet 410 and the focusing lens 408 in the
optical axis direction.
[0053] The magnet 410 has an annular shape and includes an annular
flange portion 410A projecting inwards from the distal end portion
of its inner peripheral surface in the -Y direction. The magnet 410
accommodates the focusing lens 408 and supports the focusing lens
408 through the flange portion 410A. The magnet 410 is located
outside the focusing lens 408 in the radial direction and moves
together with the focusing lens 408.
[0054] Light from the object within the oral cavity impinges on the
focusing lens 408 via the imaging window 31. The focusing lens 408
focuses the light from the object to form an object image on the
imaging device 403.
[0055] The iris 411 is positioned more to the object side than the
focusing lens 408 and narrows the light incident on the focusing
lens 408 through an aperture portion 411A.
[0056] The holding member 412 extends across the end faces of the
iris 411 and magnet 410 in the +Y direction. The holding member 412
and the flange portion 410A of the magnet 410 clamp the focusing
lens 408 and the iris 411.
[0057] In this embodiment, a lens moving mechanism 6 that moves the
focusing lens 408 in the optical axis direction includes the magnet
410, the vibrating plate 409, and the coil 407.
[0058] The operation of the intraoral camera 1 will be described
below with reference to a flowchart shown in FIG. 5.
[0059] When the power supply switch 21 is turned on (STEP 1), if
the selecting switch 25 is set at an ON position for the white LEDs
401 (YES in STEP 2), the controller 51 turns on the white LEDs 401
(STEP 3). If the selecting switch 25 is set at an ON position for
the 405-nm LEDs 402 (NO in STEP 2), the controller 51 turns on the
405-nm LEDs 402 (STEP 4).
[0060] The user operates the intraoral camera 1 to point the
imaging window 31 at an object such as a row of teeth to be
captured and presses the imaging button 22.
[0061] If the imaging button 22 is pressed and an imaging
instruction is input (YES in STEP 5), the controller 51 moves the
focusing lens 408 to a plurality of imaging positions in the
optical axis direction to obtain an image captured when the
focusing lens 408 is positioned at each of the imaging positions
and store these images in the memory 52 (STEPS 6 to 8). If the
imaging button 22 remains to be pressed (NO in STEP 5), the
controller 51 stands by unless the power supply switch 21 is turned
off (NO in STEP 10) and repeats the process from STEP 2.
[0062] FIG. 6 includes diagrams for explaining an example of a
method of moving the focusing lens 408 in imaging. (A) in FIG. 6 is
a view illustrating the position of the focusing lens 408 before an
imaging instruction is input. (B) in FIG. 6 is a view illustrating
the position of the focusing lens 408 immediately after an imaging
instruction was input, and a method of moving the focusing lens
408.
[0063] In this embodiment, the imaging position changes in 30
stages, the number of which is equal to the frame rate (30 FPS).
The imaging position is set to have an almost equal number of
stages in the +Y and -Y sides with respect to the home
position.
[0064] If the imaging button 22 is pressed and an imaging
instruction is input (YES in STEP 5), the controller 51 moves the
focusing lens 408 to the imaging position at an infinity end of the
set imaging positions (STEP 6).
[0065] At this time, the controller 51 supplies a current to the
coil 407 to make it generate a magnetic force so that the focusing
lens 408 moves to the imaging position of the infinity end and
stops at this position. The controller 51 changes the amount of
current supplied to the coil 407 in accordance with a target
imaging position, so that the focusing lens 408 moves to the target
imaging position and stops at this position.
[0066] The controller 51 moves the focusing lens 408 to the imaging
position of the infinity end (STEP 6) before the first imaging
operation at the driving timing (30 FPS) of the imaging device 403.
The controller 51 then drives the imaging device 403 at the first
driving timing of the imaging device 403.
[0067] The controller 51 obtains an image of the object captured
when the focusing lens 408 is positioned at the imaging position of
the infinity end (STEP 7), and stores the captured image in the
memory 52 (STEP 8). The controller 51 assigns 1 to metadata of the
captured image as a position number indicating that the focusing
lens 408 is positioned at the imaging position of the infinity
end.
[0068] Since imaging has not ended for all the imaging positions
(NO in STEP 9), the controller 51 moves the focusing lens 408 from
the imaging position of the infinity end to the close-up end side
by one stage (STEP 6) before the second imaging operation at the
driving timing (30 FPS) of the imaging device 403.
[0069] The controller 51 obtains a captured image (STEP 7) and
stores it in the memory 52 (STEP 8). The controller 51 assigns 2 to
metadata of the captured image as a position number indicating that
the focusing lens 408 is positioned more to the close-up end side
than the imaging position of the infinity end by one stage.
[0070] The controller 51 changes the amount of current supplied to
the coil 407, stepwise in accordance with the driving timing of the
imaging device 403 to move the focusing lens 408. The controller 51
obtains captured images while shifting the focusing lens 408 from
the infinity end side to the close-up end side for each stage by
stages, the number of which is equal to the frame rate, and stores
them in the memory 52 (STEPS 6 to 9).
[0071] The controller 51 assigns the image captured at each of the
imaging positions with a position number corresponding to the
imaging position of the focusing lens 408 as metadata, that is,
assigns these images with position numbers 1 to 30 corresponding to
the frame rate (30 FPS) (STEP 8).
[0072] When imaging has ended for all the imaging positions (YES in
STEP 9), the controller 51 returns the focusing lens 408 to the
home position and assumes a standby state (NO in STEP 10), and then
repeats the process from STEP 2. If the power supply switch 21 is
turned off (YES in STEP 10), the controller 51 turns off the white
LEDs 401 or the 405-nm LEDs 402 that are kept ON (STEP 11) and ends
the process.
[0073] If the external device 300 is implemented using a display
only, the intraoral camera 1 transmits the captured images stored
in the memory 52 to the external device 300 to allow the external
device 300 to play them back every time the playback buttons 23A
and 23B (see FIG. 1) are pressed. Images corresponding to 30 frames
captured at different imaging positions are stored in the memory 52
for each imaging operation upon one pressing operation of the
imaging button 22.
[0074] The user can change the captured image displayed on the
external device 300 to the image captured one frame before the
current image by pressing the playback button 23A (see FIG. 1) or
to the image captured one frame after the current image by pressing
the playback button 23B (see FIG. 1). The external device 300 may
simultaneously display the captured images and the position numbers
assigned to these images.
[0075] As described above, by operating the playback buttons 23A
and 23B, the user can select an in-focus captured image from the
captured images of the object corresponding to 30 frames obtained
by one pressing operation of the imaging button 22 and display it
on the external device 300.
[0076] If the external device 300 is implemented using a PC, the
external device 300 can not only play back the captured images in
the intraoral camera 1 but also read the captured images from the
memory 52 of the intraoral camera 1 and store and manage them. For
example, the external device 300 may read captured images of the
object corresponding to 30 frames every time the intraoral camera 1
obtains these images. The external device 300 may simultaneously
display the captured images and the position numbers assigned to
these images. The user may select and store an in-focus image in
the external device 300.
(Effects)
[0077] The intraoral camera 1 is limited in size because of its use
within the oral cavity. Therefore, mounting an autofocus mechanism
in the intraoral camera 1 imposes strict constraints in terms of
the size and arrangement of optical components of the autofocus
mechanism. Furthermore, the intraoral camera 1 is used under very
dark intraoral environments and requires a wide range of imaging
distance to the object because, for example, images of a row of
teeth are captured close-up or from far away.
[0078] Mounting an autofocus mechanism in the intraoral camera 1
imposes strict constraints in terms of the size and arrangement of
optical components of the autofocus mechanism. Moreover, the
intraoral camera 1 is used under environments readily influenced by
the illumination state of light illuminating the object due to an
insufficient amount of light. It is therefore difficult for the
autofocus mechanism to achieve highly accurate focusing.
[0079] To solve the above-mentioned problems, in this embodiment,
an autofocus mechanism is intentionally omitted. Instead, every
time an imaging instruction is input, the focusing lens 408 is
moved to a plurality of imaging positions in the optical axis
direction to obtain captured images. In this embodiment, therefore,
it is possible to reliably obtain an in-focus image.
[0080] In the conventional intraoral camera 1 that uses an
autofocus mechanism, the autofocus mechanism cannot be placed in
the insertion portion 3 and must be placed in the gripping portion
2 in terms of its size. Hence, the conventional intraoral camera 1
cannot be equipped with the battery 24 and therefore must be
connected to an external power supply by wiring. The intraoral
camera 1 performs precise operations and thus may be hard to use in
the presence of wiring. As another problem, the conventional
optical system for imaging includes an autofocus mechanism and is
therefore heavy, as described in "BACKGROUND OF THE INVENTION."
[0081] The use of an autofocus mechanism requires arranging, in the
insertion portion 3, optical components for guiding light received
from the imaging window 31 of the insertion portion 3 to the
autofocus mechanism in the gripping portion 2 and the imaging
device 403. In this embodiment, an autofocus mechanism is omitted.
This makes it possible to place the imaging unit 4 at the distal
end portion of the intraoral camera 1 and obviates the need for the
optical components. In this embodiment, therefore, it is possible
to obviate the need for the optical components and an autofocus
mechanism and provide a compact, lightweight optical system for
imaging (imaging unit 4).
[0082] The controller 51 changes the value of current supplied to
the coil 407 stepwise in accordance with the driving timing of the
imaging device 403, to thereby allow the focusing lens 408 to move
at high speed to a plurality of imaging positions between the
infinity and close-up ends.
[0083] In this embodiment, since the imaging unit 4 can be
positioned at the distal end portion of the intraoral camera 1, the
battery 24 can be positioned in the gripping portion 2 to attain
wireless communication by the intraoral camera 1.
[0084] As described above, in this embodiment, miniaturization and
reduction in weight of an optical system for imaging and wireless
communication for an intraoral camera 1 are simultaneously
achieved.
[0085] Assume that in the imaging unit 4, the coil 407 is fixed to
the focusing lens 408 and the magnet 410 is fixed to the holder
406, in contrast to the configuration according to this embodiment.
Then, the coil 407 must be wired into the holder 406 from the
outside of the holder 406. This complicates the structure of the
imaging unit 4 and increases the cost.
[0086] In this embodiment, since the coil 407 is fixed to the
holder 406 and the magnet 410 is fixed to the focusing lens 408,
the coil 407 need not be wired into the holder 406. This can
simplify the structure of the imaging unit 4 and reduce the cost in
this embodiment.
[0087] In this embodiment, the imaging position changes in stages,
the number of which is equal to the frame rate of the imaging
device 403. This simultaneously achieves setting of a number of
stages of the imaging position sufficient to obtain an in-focus
image and shortening of the imaging time taken for one pressing
operation of the imaging button 22.
[0088] In this embodiment, since position numbers corresponding to
the imaging positions of the focusing lens 408 are assigned to the
captured images as metadata, these images can be easily
managed.
Second Embodiment
[0089] FIG. 7 is a cross-sectional view illustrating an example of
a capsule endoscope 1A to which an imaging apparatus according to
the present invention is applied.
[0090] In the capsule endoscope 1A, a case 310 extends in the
horizontal direction of FIG. 7 and has a central axis XA. The case
310 includes, at its distal end, a transparent portion 311 which
transmits light. The case 310 accommodates an imaging unit 4A
opposed to the transparent portion 311. The imaging unit 4A is
oriented so that the optical axis of a focusing lens 408 is tilted
with respect to the central axis XA.
[0091] The imaging unit 4A includes a plurality of LEDs 413 which
emit light beams having different wavelengths, the focusing lens
408, a magnet 410, a coil 407, and an imaging device 403, as in the
first embodiment.
[0092] The capsule endoscope 1A moves in a living body while the
imaging unit 4A is assuming an attitude that enables imaging of
objects seen ahead in the moving direction. The capsule endoscope
1A is pushed forwards in the moving direction by small intestinal
peristalsis while being in press contact with, for example, the
wall surface of the small intestine.
[0093] Electromagnetic energy is sent from the outside of the
living body to the capsule endoscope 1A. Upon receiving the
electromagnetic energy from the outside of the living body by a
power-generating magnetism receiving coil (not shown), the capsule
endoscope 1A causes the coil to generate and supply power to, for
example, a controller (not shown) and the imaging unit 4A.
[0094] The capsule endoscope 1A has three rotor coils (not shown)
arranged at intervals of 60.degree. with the central axis XA as its
center. When the user wears a vest embedded with three stator
coils, the three stator coils are set outside the living body.
Controlling the rotor coils in the capsule endoscope 1A and the
stator coils outside the living body makes it possible to
circumferentially rotate the imaging direction with respect to the
moving direction (central axis XA).
[0095] As described above, the capsule endoscope 1A
circumferentially rotates the imaging direction and continuously
captures images while moving in, for example, the small intestine.
The capsule endoscope 1A obtains captured images while shifting the
imaging position of the focusing lens 408 from the close-up end
side to the infinity end side for each frame rate, as in the first
embodiment. In this embodiment, the capsule endoscope 1A has no
memory and transmits the captured images to an external device via
a transmitter (not shown). Hence, an in-focus captured image can be
selected and used for, for example, medical diagnosis on the
external device.
Third Embodiment
[0096] FIG. 8 is a cross-sectional view illustrating an example of
a capsule endoscope 1B to which an imaging apparatus according to
the present invention is applied.
[0097] The capsule endoscope 1B has a double-case structure and
includes an outer case 312 and an inner case 313 positioned inside
the outer case 312. The inner case 313 can rotate about a central
axis XB. The outer case 312 has, at its longitudinal central
portion, a transparent portion 314 formed over the entire
circumferential length. The inner case 313 has, at its longitudinal
central portion, a transparent portion 316 as well. A plurality of
LEDs 414 which emit light beams having different wavelengths
surround the transparent portion 316. A magnet 315 is provided on
the side of one end in the outer case 312.
[0098] An imaging unit 4B is opposed to the transparent portion 316
in the inner case 313 and captures images of the interior walls of,
for example, a small intestine via the transparent portions 316 and
314. A controller 51 is provided on the back side of an imaging
device 403 of the imaging unit 4B. In the inner case 313, a
power-generating magnetism receiving coil 317 is positioned so that
the imaging unit 4B is interposed therebetween along the central
axis XB. An attitude control coil 318 surrounds the magnet 315 on
the side of one end in the inner case 313, and a transmitter 319 is
provided on the side of the other end in the inner case 313.
[0099] Upon receiving electromagnetic energy from the outside of
the living body by the power-generating magnetism receiving coil
317, the capsule endoscope 1B causes the coil to generate and
supply power to the attitude control coil 318, to thereby rotate
the inner case 313 about the central axis XB by interaction with
the magnet 315 and circumferentially rotate the imaging direction
with respect to the moving direction (central axis XB).
[0100] The capsule endoscope 1B circumferentially rotates the
imaging direction and continuously captures images while moving in,
for example, the small intestine. The capsule endoscope 1B obtains
captured images while shifting the imaging position of the focusing
lens 408 from the close-up end side to the infinity end side for
each frame rate, as in the first and second embodiments. The
capsule endoscope 1B transmits the captured images to an external
device via the transmitter 319.
Fourth Embodiment
[0101] FIG. 9 is a cross-sectional view illustrating an example of
a joystick endoscope 1C to which an imaging apparatus according to
the present invention is applied.
[0102] The joystick endoscope 1C is used to capture images of
objects at sites hard to capture, including the interiors of narrow
tubes and a body. Since the basic structure of the joystick
endoscope 1C is the same as that described in Japanese Patent
Application Laid-Open No. 2009-89955, a brief description thereof
will be given herein.
[0103] A pivotally movable operation member 81 is provided at one
end of the joystick endoscope 1C and a bendable hollow pipe member
82 is provided at its other end. An imaging unit 4C as in the first
to third embodiments is provided at the distal end of the pipe
member 82. The imaging unit 4C captures an image of an object seen
in the direction in which the pipe member 82 is pointed. The
imaging unit 4C is connected to a controller (not shown) by wiring
83. Since the operation member 81 is connected to the pipe member
82 via a plurality of wires 84, pivoting the operation member 81
makes it possible to bend the pipe member 82 in an appropriate
direction and operate the imaging direction.
[0104] The joystick endoscope 1C obtains captured images while
shifting the imaging position of a focusing lens 408 of the imaging
unit 4C from the close-up end side to the infinity end side for
each frame rate, as in the first to third embodiments. The joystick
endoscope 1C may store the obtained, captured images in a memory to
play them back on an external device, as in the first embodiment.
Alternatively, the joystick endoscope 1C may transmit the captured
images to an external device, as in the second and third
embodiments.
[0105] Although the joystick endoscope 1C is used in this
embodiment, an endoscope having another structure can also be used.
That is, an imaging unit 4C as in this embodiment can be positioned
at the distal end of the elongated pipe member 82.
(Modification)
[0106] The imaging position of the focusing lens 408 may be moved
for each stage from the close-up end to the infinity end. The
imaging position may be set only in one of the +Y- and -Y
directions from the home position. The distance between two imaging
positions adjacent in the optical axis direction may be different
or equal. The home position can be set to an arbitrary imaging
position ranging between the infinity and close-up ends. For
example, the home position can be set to the infinity or close-up
end.
[0107] A plurality of captured images can also be obtained at a
predetermined imaging position by a plurality of imaging operations
without changing the imaging position. In this case, the number of
imaging positions to which the focusing lens 408 is moved is
smaller than the number of the frame rate. Although a position
number corresponding to the imaging position is assigned to a
plurality of captured images obtained at the same imaging position,
different position numbers can also be assigned to distinguish a
plurality of captured images obtained at the same imaging position
from each other.
[0108] In obtaining a plurality of captured images at a
predetermined imaging position, the number of captured images may
be equal or different for all imaging positions. When the number of
captured images is set equal for all imaging positions, the number
of stages of the imaging position can be set to a value obtained by
dividing the frame rate (30 FPS) by an integer of 2 or more. The
number of stages of the imaging position can be set to, for
example, 10 obtained by dividing the frame rate (30 FPS) by 3.
[0109] A plurality of captured images can be continuously played
back in the order (ascending or descending order) of position
number on the external device 300. Thus, the user can continuously
confirm a plurality of captured images on the external device 300
and easily select an in-focus captured image. When an in-focus
captured image is selected and a position number corresponding to
this image is input to the external device 300, the selected,
captured image can be confirmed again.
[0110] When a plurality of captured images are obtained at a
predetermined imaging position, and input of a position number is
accepted, the external device 300 can simultaneously display a
plurality of captured images corresponding to the input position
number.
[0111] The controller 51 may determine a captured image having a
highest frequency component of the captured images as an in-focus
captured image, and assign metadata indicating a best-focus image
to this image. The controller 51 may store only the best-focus
captured image in the memory 52 or display it on the external
device 300.
[0112] When a best-focus image is specified, the controller 51 can
specify the distance from the focusing lens 408 to the object, on
the basis of the imaging position corresponding to the best-focus
captured image. More specifically, the distance from the focusing
lens 408 to the object can be specified on the basis of the focal
length of the focusing lens 408 and the distance from the focusing
lens 408 to the imaging device (imaging plane) 403 which is
specified from the imaging position. Note that as long as the
relationship between the imaging position and the amount of power
supplied to the coil 407 is obtained in advance, the imaging
position, that is, the distance from the focusing lens 408 to the
imaging device 403 can be specified by detecting the amount of
power supplied to the coil 407. The controller 51 can display the
distance from the focusing lens 408 to the object on the external
device 300. Thus, the user can determine the position of the
intraoral camera 1 or an imaging apparatus according to the present
invention, represented by an endoscope such as the joystick
endoscope 1C described in Embodiment 4, with respect to an object
in capturing an image of the object using the intraoral camera 1 or
the imaging apparatus.
[0113] In the imaging unit 4, the coil 407 may be fixed to the
focusing lens 408 and the magnet 410 may be fixed to the holder
406.
[0114] The intraoral camera 1 need not always include the battery
24 and may be connected to an external power supply by wiring.
REFERENCE SIGNS LIST
[0115] 1: intraoral camera (imaging apparatus) [0116] 6: lens
moving mechanism (moving mechanism) [0117] 10: case [0118] 51:
controller [0119] 52: memory [0120] 403: imaging device [0121] 407:
coil [0122] 408: focusing lens (lens) [0123] 409: vibrating plate
[0124] 410: magnet
* * * * *